Exposure method and apparatus

Abstract

A method of exposing a photosensitive substrate with a band-narrowed laser beam from an excimer laser includes providing a stop having an opening in a path of the laser beam; adjusting a size of the opening of the stop to substantially compensate for a change in bandwidth of the laser beam; and exposing after the adjustment the substrate with the laser beam.

What is claimed is: 
     
       1. A method of exposing a photosensitive substrate with a band-narrowed laser beam from an excimer laser, said method comprising the steps of: detecting a change in bandwidth of the laser beam;   changing the diameter of the laser beam to substantially compensate for the change in bandwidth of the laser beam; and   exposing the substrate with the diameter-changed laser beam.   
     
     
       2. A method according to claim 1, wherein said changing step comprises providing a stop having an aperture of adjustable size in the path of the laser beam. 
     
     
       3. A method according to claim 2, wherein the excimer laser includes a resonator having a diffraction grating disposed therewithin, and wherein the size of the opening is adjusted by changing the width of the opening in a direction corresponding to a direction perpendicular to a grating line of the diffraction grating. 
     
     
       4. A method according to claim 2, wherein the size of the opening is adjusted by changing the width of the opening that corresponds to a smaller dimension of a cross-section of the laser beam. 
     
     
       5. A method according to claim 3 or 4, wherein a sectional intensity distribution of the laser beam is monitored to detect the change in the bandwidth. 
     
     
       6. A method according to claim 2, wherein the excimer laser comprises a KrF excimer laser. 
     
     
       7. A method according to claim 2, wherein the laser beam passing through the opening of the stop is directed to the substrate through a lens assembly, for exposure of the substrate. 
     
     
       8. A method according to claim 7, wherein the size of the opening is adjusted so as to provide a laser beam of a bandwidth not greater than 0.005 nm. 
     
     
       9. A method according to claim 8, wherein the size of the aperture is adjusted so as to provide a laser beam of a bandwidth not greater than 0.003 nm. 
     
     
       10. A method according to claim 7, wherein the lens assembly is made substantially of a single glass material. 
     
     
       11. A method according to claim 10, wherein the glass material includes synthetic quartz as a major component. 
     
     
       12. A method of manufacturing semiconductor devices by exposing a photosensitive layer of a wafer to a band-narrowed laser beam from an excimer laser to print a circuit pattern on the photosensitive layer, said method comprising the steps of: detecting a change in bandwidth of the laser beam;   changing the diameter of the laser beam to substantially compensate for the change in bandwidth of the laser beam; and   exposing the wafer with the diameter-changed laser beam to print the circuit pattern on the wafer.   
     
     
       13. A method according to claim 12, wherein said changing step comprises providing a stop having an aperture of adjustable size in the path of the laser beam. 
     
     
       14. A method according to claim 13, wherein the circuit pattern is illuminated with the laser beam passing through the opening of the stop, and wherein an image of the circuit pattern is projected on the wafer by a projection lens system, for exposure of the wafer. 
     
     
       15. A method according to claim 14, wherein the excimer laser includes a resonator having a diffraction grating disposed therewithin, and wherein the size of the opening is adjusted by changing the width of the opening in a direction corresponding to a direction perpendicular to a grating line of the diffraction grating. 
     
     
       16. A method according to claim 14, wherein the size of the opening is adjusted by changing the width of the opening that corresponds to a smaller dimension of a cross-section of the laser beam. 
     
     
       17. A method according to claim 15 or 16, wherein a sectional intensity distribution of the laser beam is monitored to detect the change in the bandwidth. 
     
     
       18. A method according to claim 14, wherein the lens assembly is made substantially of a single glass material. 
     
     
       19. A method according to claim 18, wherein the glass material includes synthetic quartz as a major component. 
     
     
       20. A method according to claim 19, wherein the size of the opening is adjusted so as to provide a laser beam of a bandwidth not greater than 0.005 nm. 
     
     
       21. A method according to claim 20, wherein the size of the aperture is adjusted so as to provide a laser beam of a bandwidth not greater than 0.003 nm. 
     
     
       22. A method of exposing a photosensitive substrate with a band-narrowed laser beam, said method comprising the steps of: detecting a change in bandwidth of the laser beam;   changing the diameter of the laser beam to substantially compensate for the change in bandwidth of the laser beam; and   exposing the substrate with the diameter-changed laser beam.   
     
     
       23. A method according to claim 22, wherein said changing step comprises providing a stop having an aperture of adjustable size in a path of the laser beam. 
     
     
       24. A method according to claim 22, wherein said exposing step comprises focusing the laser beam onto the substrate by a projection lens. 
     
     
       25. A device manufacturing method including a step of exposing a photosensitive substrate with a band-narrowed laser beam to print a device pattern on the substrate, said method comprising the steps of: detecting a change in bandwidth of the laser beam;   changing the diameter of the laser beam to substantially compensate for the change in bandwidth of the laser beam; and   exposing the substrate with the diameter-changed laser beam.   
     
     
       26. A method according to claim 25, wherein said changing step comprises providing a stop having an aperture of adjustable size in a path of the laser beam. 
     
     
       27. A method according to claim 25, wherein said exposing step comprises focusing the laser beam onto the substrate by a projection lens. 
     
     
       28. A method of exposing a photosensitive substrate with a band-narrowed laser beam, said method comprising the steps of: providing a variable aperture in a path of the laser beam;   detecting a change in bandwidth of the laser beam; and   substantially compensating for the detected change in bandwidth of the laser beam by changing the width of the aperture.   
     
     
       29. A method of manufacturing a device by exposing a photosensitive substrate with a band-narrowed laser beam to print a device pattern on the substrate, said method comprising the steps of: providing a variable aperture in a path of the laser beam;   detecting a change in bandwidth of the laser beam; and   substantially compensating for the detected change in bandwidth of the laser beam by changing the width of the aperture.